Differential pressure charging apparatus



NOV- 8, 1955 s. T. GOLDEN DIFFERENTIAL PRESSURE CHARGING APPARATUS Filed Oct. 28, 1954 Ea. l.

United States Patent ffice 2,723,057 Patented Nov. 8, 1955 DIFFERENTIAL PRESSURE CHARGING APPARATUS Steven T. Golden, Marana, Ariz.

Application October 28, 1954, Serial-No. 465,308

11 Claims. (Cl. 222-442) This invention relates generally to charging apparatus for owable materials, either solid or liquid,y and particularly describes such a device suitable for use in connection with equipment. for applying, under fluid pressure, material such as expanded perlite, concrete, sand, etc.

In its preferred form as hereinafter shown and described, the invention includes a hollow, vertically oriented housing provided with inlet gate valve means at the top and outlet gate valve means at the bottom. The housing thus constitutes a closable charging chamber and is arranged to be mounted beneath al source of material to be charged into a pressure line, such source being typically a supply hopper or the like. The lower or outlet gate valve of the housing communicates downwardly with a second chamber which is provided with inlet means connected to a source of uid' pressure and outlet means adapted to be connected to suitable applicating means. such as a exible hose or the like which may be guided by the operator to deposity material undery pressure ata desired location.

Sincey the supply of material to be charged is normally under only atmospheric pressure and since the material to be charged must be miXedi with fluid, typically water or air, which is under a` working pressure of 50 pounds per square inch or more, the pressure to which the material is subjected must be increased fromv substantially atmospheric to the working pressure. Apparatus for accomplishing this forms the subject matter of this invention. Within the charging` chamber mentioned above, the present invention includes duid-energized', valve actuating means for controlling the inlet and outlet gate valves heretofore mentioned. Desirably, the valve actuating. means consists of a single actuating chamber in the form of a vertically oriented? cylinder having a pair of axially aligned actuating` pistons slidably mounted within the cylinder. Each. of the pistons is` attached as by an axially movable piston rod to movable closure members of one of the two gateY valves. Pilot valve means are providedV for controllably introducing pressure iluid'into.- the central` portion of the actuating chamber, between the inward limits of.` travel' ofthe two pistons and. for bleeding pressure therefrom'. The opposite ends of the actuating chamber are interconnected by suitable conduit means and the apparatus includes selectively actuable pilot valve means for introducing uid into or bleeding fluid from the' ends of the actuating chamber.

Means are also provided. for introducing pressure fluid into and bleeding pressure fluid from the interior ofthe charging chamber. Desirably, the pressure uid controlled' by the several pilot valves just mentioned may be the samel pressure fluid as that'usedfto force the material out ofthe. mixing chamber for further use asin spraying or the like.

Much of the material usedv in connection with apparatus of the present character isl of` a rough or abrasive nature, and a principal disadvantage `ofprorcharging apparatus has been the serious problem of valve wear encountered and. consequent inoperability of the apparatus after a short period of' use. The inlet and outlet gate valves in they present apparatus are particularly designed to withstand such abrasive use and in their preferredI forms include circular seats formed inthe housing and movable closure members made of rubber or similar material. The closure membersV are preferably provided with a convex upper surface, and include rigid backing plates. Thediameterl of the convex closure member is appreciably greater than that of the circular seat, and the valve will sealingly contact the seat, when in closed position, over a very longperiod of time without failure or pressure leakage.

The several pilot valves controlling the application of pressure fluid to the pressure chamber and charging chamber are so manipulated byl an operator or by suitable automatic means as to take advantage of differential pressures existing within the actuating, chamber, the, Charging chamber and the mixing or pressure chamber in controlling the opening and closing of the inlet and. outlet gate valves of the charging chamber.

An object of the present invention is therefore to dis.- close novel apparatus for charging ilowable material into a pressure chamber.

Another object of the invention is to disclose apparatus of the above character including a vertically oriented charging chamber having inlet and outlet gate valves and a vertically oriented valve actuating. chamber within the charging chamber.

A further object of theA inventonis to provide, in charging apparatus having a valved charging chamber, improved valvel constructie-n resisting abrasion over -a long period of use.

Another object is to disclose, in charging apparatus having reciprocable gate Valves adapted to be moved rapidly from open tor closed positions, means. forminimizing damage caused by shock and vibration of moving parts.

Yet another object ofthe invention is to disclose charging or transfer apparatus for owable' material including differential pressure actuated gate valve means.

A further object is to disclose apparatus having the above characteristics so arranged to facilitate maintenance and replacement oi' component parts.

These and other and' allied objectsV and purposeslof the invention will be understood from a study ofthe fol'- lowing description vofl a preferred, embodiment thereof taken in connection with the accompanyingv drawings illustratively showing such embodiment..

In the drawings:

Fig. l is a vertical sectional view of charging apparavtus in accordance with the present inventionfmounted beneath a supply hopper. The, upper inlet gate valve is open and the lower outlet gate valve is closed sothatmaterial may move from the supply hopper into the charging chamber; I

Fig. 2 is a fragmentary sectional view of the apparatus of Fig. l showing both inlet and outlet gate valves closed andl pressure iluid being introduced. into the charging chamber.

Fig. .3` is a View similar toFi'g. 2 showing the parts later in the cycle of operation, the outlet gate valve being open to discharge material under pressure into the pressure or mixing chamber.

Fig. 4 is a vertical sectional view similar to Figs.. 'l and 3 showing. the apparatus later in the cycle than that shown in Fig. 3 with the lower outlet gate valve closed and pressure il'uid being bled from the charging. chamber.

Referring now` in' detail' to the drawing, a supply hopper is indicated generally at 10 and a charging chamber is indicated generally at 12 in the formait" a hollow. vertically c )ri'ented'anddesirablyI cylindrical housing or Agraz-3,0157

shell disposed beneath the hopper 10. A pressure mixing chamber indicated generally at 14 is fixed beneath the charging chamber 12. The housing 12 is provided with upper inlet gate valve means including a iixed circular seat 16 which is downwardly directed and is adapted to be sealingly contacted by a vertically movable closure member 18 made of rubber or a similar resilient material. Desirably the upper portion of closure member 18 is convex and takes the form of a portion of a sphere .having a substantially greater diameter than that of thevcircular fixed gate valve seat 16. A rigid backing plate 19 is disposed beneath the resilient member to afford strength to the assembly. Lower outlet gate valve means are provided in the housing 12 including a circular downwardly directed seat 20 fixed to the housing and a vertically movable resilient closure member 22 and rigid backing plate 23 similar in construction to the upper closure member 18.

Means are provided within the charging chamber 12 for actuating the closure members 18 and 22 into, selectively, open or closed positions. In the present illustration such means include hollow shell constituting an actuating chamber generally indicated at 30 carried by suitable support members 31 and 32 desirably in the form of metal straps extending inwardly from the cylindrical wall of charging chamber 12 and fixed to thc pressure chamber 30 in suitable manner. Actuating chamber 30 is preferably cylindrical, and slidably mounted therein is an upper actuating piston 35 having an upwardly extending piston rod 36 connected thereto by suitable means 37. The piston rod 36 projects outwardly from pressure chamber 30 through conventional pacl;- ing means or gland 38 formed in the upper cap 40 closing pressure cylinder 30 and preferably threadedly attached thereto at 42. The upper end of piston rod 36 extends through and is fixed to the upper closure member 18 as by a nut 44 threadedly engaging the upper end of the piston rod and by a second nut 45 disposed beneath the backing plate 19. Resilient means are provided for limiting downward movement of the closure member 18. Such resilient means are here illustratively shown as a helical coiled spring 47 surrounding piston rod 36 and resting upon the central boss of cap 40; the spring is adapted to contact nut 45 when the closure member moves to open position.

Within actuating chamber 30 there is also slidably mounted a lower piston 50 having connected thereto by suitable means 52 a downwardly extending piston rod 54. The piston rod 54 projects outwardly of actuating lchamber 30 being slidably carried in gland means 56 centrally disposed in lower cap 58 which is connected across the lower end of actuating chamber 30 as by threaded connection 60. The gate valve closure member 22 previously referred to is carried on the lower portion of the piston rod 54, being connected thereto preferably by nuts 62 and 63 threaded to the piston rod 54. the nut 63 bearing upwardly against the backing plate 23 of the lower gate valve closure member. Spring 55 resiliently determines the lower limit of travel of piston 50.

Means are provided for introducing pressure fluid into the central portion of actuating chamber 30 between the actuating pistons 35 and 50. These means are here shown as including a pressure conduit 65 communicating through port 66 with the interior of pressure chamber 30, the outer end of conduit 65 extending through the housing 12 of the charging chamber and being connected to a pilot valve indicated generally at 68. The pilot valve 68 is supplied through conduit 70 with pressure iiuid from a suitable source 72. l'n most instances the pressure uid supplied to the present apparatus through the conduit 70 will be compressed air, although, as will be understood, other material including liquids may be used if desired.

Means are provided for introducing pressure uid from conduit 70 into opposite ends of actuating chamber 30. In the present illustration such means includev a, Conduit.

interconnecting the upper and lower ends of cham- 'ber 30 through ports 76 and 77, conduit 7 8 communicating the upper end of chamber 30 through port 79 with control pilot valve indicated generally at Si) which in turn communicates with pressure fluid in the conduit 70.

rl`he apparatus is also provided with means for controllably introducing pressure uid into the charging chamber 12. Such means are here illustrated as including a conduit 82 communicating with charging chamber 12 through port 84, and pilot control valve 85 connected to pressure fluid conduit 70. Each of the pilot control valves 63, 8? and 85 is arranged to be selectively movable to introduce pressure uid into its respective conduit 65, 78 and 82 from the conduit 70 or to bleed pressure iiuid from its respective conduits through vent openings 69, 81 and S6.

At the lower end of the charging chamber 12, the mixing or pressure chamber 14 is preferably removably attached thereto by means 90, and the mixing chamber includes an inlet opening 92 connected to pressure liuid conduit 70 and an outlet opening 93 connected to an outlet conduit 94. The outlet conduit may be a exible hose or the like adapted to be connected to a suitable applicating means, not shown, such as a cement gun for spraying concrete, to a Sandblasting nozzle or to other apparatus well known in the art for applying under pressure the particular material charged by the present apparatus. Although the inlet opening 92 is here shown as connected to the same source of pressure fluid 72 as that which is used in actuating the valves of the present apparatus, nevertheless, it will be evident that the inlet opening 92 may instead be connected to any other desired source of pressure iiuid intended to be introduced into the mixing chamber 14 and to force outwardly through outlet conduit 94 the owable material being handled. Desirably, the pressure uid introduced in inlet opening 92 is of substantially the same pressure as that supplied to the valve-actuating chamber and the charging chamber, whose operation will be now described.

With the parts in the position shown in Fig. l, the lower gate valve closure member 22 is held in its upper or closed position as shown both by the pressure existing within the mixing chamber 14 as well as by pressure existing within the lower portion of actuating chamber 30. It will be noted that this latter uid pressure is directed upwardly against the lower face of piston 50 and only atmospheric pressure exists in the central portion of actuating chamber 30 since the pilot control valve 68 is in position to vent the pressure within conduit 65 through vent opening 69. The upper gate valve closure member 18 is held in its open position since pressure fluid in the upper portion of actuating chamber 30 is exerted downwardly upon piston 35. The pilot control valve 85 is in vented position as shown during this portion of the cycle. Material in supply hopper 1i) will, therefore, fall under the inuence of gravity into the charging chamber 12.

When suflicient material has entered the charging chamber 12, the upper gate valve closure member 18 is moved upwardly to its closed position by force developed within actuating chamber 30 and exerted upwardly on piston 35. Thus pilot control valve is moved to its venting position (as seen in Fig. 2) and pressure duid is introduced into the central portion of actuating chamber 30 through conduit 65, pilot control valve 68 being moved to pressure-uid-supplying position. Pressure uid is now introduced into charging chamber 12 through pilot control valve as the pressure within charging chamber 12 approaches the pressure existing within pressure-mixing chamber 14, the lower gate valve closure member 22 will be caused to open. This results from static differential downward force applied to the lower closure member 22 and by reason of the force developed within actuating chamber 30 and applied downwardly upon the upper face of piston 50 and thence through the piston rod 54 to the closure member 22.

Opening of the lower gate valve closure member 22 A hat'.

permits.` gravity il'owy of: the material fromI Within charging chamber-'12 into the; pressure-mixing chamber 1'5; as illustrated in Eig. 3".. Downwardl'ow'of materiali into the pressure-mixing chamber 142 permitted' to continue until charging chamber 12- is virtually-empty.y

Closingv of the lower gate valve closure member 22' is accomplished by creatingforcewithin the actuating chamber-30 by which to urge piston. 50 upwardly' against the force of gravity. Accordingly, pilot controlf valve '68 is moved from its pressure-applying position. shown in- Fig. 3, to venting positiony as seen in Fig. 4tand pilot control valvekv 80 is moved from its venting positionI offFig. 3y to pressure-applying position ofA Fig. 4. Since thetuid pressure within mixing chamber 14 isv substantially equal to that in charging chamber 12, the upward'` force thus exerted upon piston` 50 within` actuating chamberv 30 moves that piston, togetherwith lower closure member 22 attached thereto, upwardly; toward upper position as seen in Fig. 4. At this point movementy ofi pilot control valve 85 from its pressure-applying position of Fig.; 3 to its` venting position of Fig. 4 allows the lower` closure member 22t'o complete its upward? movement into; closed position as seen in Fig. 4' and simultaneously relieves-upward pressure upon the lupper closure member 18; thus permitting the upper closure member to movedownwardly toward' open position as shown'indotted'l outline in Fig. 4. With the upper gate valve 1i8f in itsf fully opened position and lower gate valve 22 fully closed, the charging chamber 12 may be re-supplied' by gravity' flow, with material from supply hopper 10 as shown inFi'g. l.

The complete cycle of operation as above described occurs in a periodof time offfrom. one to iive seconds, depending upon a number of factors including the flowability of material being charged; thepressure of iluids-upplied bythe source 72, and' the-'physicali dimensions of the several components of the structure, particularly' the actuating chamber 30", the pistonl rods 36 and; 54- and" the upper andv lowervalve seats 1-6 andi20 Ina typicali i'nstallation, the diameter of chargingchamber l2 maybe i of the order of" one foot, the gate valveI seats 16 and- 20 being approximately half that dimensionin diameter. Pi'ston rods 36 and* 54v may be one inch: orl lessy inA diameter. The actuating chamber 30 i's desirably considerably smaller in diameterthan that of' the gate valve seats 16 and 20; adiameten of twoinches is` illustrative.` The uid" pressure may be from 50`=to- 70 lbs.` per square inch inV an installation ofthe type just illustrat-ivelyf'mentioned. It is to be distinctlyunderstood' that' the dimensions suggested are exemplary only of/a workable apparatus, and the dimensions may be widelyvaried-inorder to accommodate the structurer to particular requirements of' an application.

With further reference to the, varying of dimensions of structural members of they present invention, it will be observed that the elective area of the closure member 18 exposed to pressure iluid within charging chamber is diminished by the cross-sectional area of the piston rod 36. Moreover, the eiective area of the upper surface of piston 35 exposed to pressure uid in the upper portion of actuating chamber 30 is similarly diminished by the area of the piston rod. Since the pressures in the charging chamber 12 and in the upper portion of actuating chamber 30 are different from one another at times during the cycle of operation of the present invention, the diameter of piston rod 36 may be varied in order to achieve optimum performance of the apparatus under widely varying conditions. This variation may be accomplished by any suitable means such as providing a plurality of caps 40 having a series of gland openings 38 of gradated diameters to correspond with a series of similarly gradated rods 36.

Thus the diameter of rod and gland opening may be selected, either empirically or analytically, by which t permit the apparatus to function most elfectively under any given conditions of pressure, viscosity or owability ularlyl compact-,bv reason of incorporating the valve-actu- 6 of'mat'erial to be.y charged, and otherrelevantr factors I`n= general Il prefer that the effective. area of the. upper closure member IS--that is, the area ,off opening? 1:6"mi'nus the area of rod 36-be at least about iivei time-s effective area off the upper surface of piston 35--that;.is, thearea of piston 35 minus the area of rod 36.

In: similar manner the diameterv of: lower piston rod 542 and ofA gland 56. in lower capI 5'8.lv may bev selected by the provision: ofv apluralityA of` these members having gradated diameters.

It will be further understood that thepresent invention is. adaptedv to be used in connection. with any'desired` de.- vicel or apparatus in: theA pressure-mixing chamber 1x4; rIihis.may-f'or example,.takelthe form shown in the-Wadss worthv Patent No. 1,171,286; when the presentv apparatus is` used iny connection with a4 sand-blasting operation or avl rotatable. feed member may be. incorporated the pressure-mixing chamber as illustrated, for example, in the Domina Patent No. 1,943,589.

In the present apparat-us it is; particularly to be.J noted that the gate valve closure members 18 and 22': and'. their actuating pi-stons 3S and: 5.0: are: arrangedin verticali alignment; within the charging chamber 12 andstressesa andi vibration incident to operation; are" hence reduced to a7 minimum. Reduction of vibration is further enhanced-because thev limits of travel. of the gate valve closure membersy are themselves resilientlydetermined'. The closure members proper are desirably made of a resilient materiali, aspreviously described, and. their movement into closed position. isy therefore. Virtually shock-free.- Movement of.y the closure members into their open positionsV is; also resiliently controlled by reason of. thefresilient springmembers 47i and; 55 for the upperl and: lower closure membersy respectivelly by which the downward limit of travel of. the closure. members is.v defined. The apparatus is. particating mechanism, within. the. charging; chamberl housing.

For; clarity of understanding, the, pilot control valves 68, 8.0. and havey been shown; sclziematicallyv hereinb ut it will be understoodv that any well-known type: of: threelway control valves may be used; these valves, maybe actuated in. desired sequence by" solenoid orother automatic control means.v

Modifications. and changes.: from` the. specic forms: of the invention shown herein and typical dimensions of component partsV above suggested mayl be made without departing from the. essence of theinventionl as. delinedzin the appended claims.

I claim: v

l. Charging apparatus, including: a. hollow housing having a vertically disposed charging; chamber: therein; upper and: lower openings in. thehousing; including downwardly facing circular valve. seats;` a` hollow.l body.' within the chamberI andi lxed to thehousing.y having a; cylindrical actuating chamber therein in vertical axial alignment with said seats, said body including upper and lower end walls provided with axially disposed bores therethrough and a port formed in the side wall of the body intermediate said end walls; a fluid conduit interconnecting the upper and lower ends of the actuating chamber; upper and lower pistons Islidably mounted in said actuating chamber; upper and lower piston rods connected to said upper and lower pistons and respectively extending above and below the actuating chamber through said bores; closure members carried on the outer ends of said rods, each closure member including an upwardly facing convex resilient portion and a lower transverse rigid backing plate, said resilient portions being of greater diameter than said valve seats and adapted to sealingly contact the seats when the closure members are at their upper limits of travel; resilient means limiting the lower limits of travel of said upper closure means and said lower piston; a source of pressure lluid; conduits communicating said port, and end of said actuating chamber and the upper end of said charging chamber with said source; and control valves in the last named conduits for selectively supplying pressure fluid .to and bleeding uid from the port, the end of the actuating chamber and the upper end of the charging chamber.

2. Charging apparatus comprising: a vertically disposed hollow housing forming a charging chamber; a hollow body constituting a cylindrical actuating chamber within the charging chamber including conduit means interconnecting each end of the actuating chamber, the body wall having a port formed therein spaced from the ends thereof; upper and lower pistons vertically slidable in the actuating chamber provided with upper and lower piston rods respectively extending outwardly thereof; upper and lower gate valves in said housing including vertically movable closure members connected to said upper and lower rods respectively, each said member being closed when in raised position; and means for controllably applying pressure tluid to and bleeding pressure fluid from said charging chamber, said conduit means and said port.

3. The invention as -stated in claim 2 wherein said gate valves include circular valve seats of greater diameter than that of said actuating chamber.

4. The invention as stated in claim 3 wherein said closure members are of resilient material having a convex upper surface.

5. In charging apparatus: a vertically disposed housing having a charging chamber therein; upper inlet valve means including a first downwardly directed valve seat carried by the housing and a first vertically movable closure member below the seat and adapted to seal therewith when in upper closed position; lower outlet valve means including a second downwardly directed valve seat carried by the housing and a second vertically movable closure member below said second seat and adapted to seal therewith when in upper closed position; a longitudinal hollow body within the chamber having an actuating chamber formed therein and upper and lower vertically slidable pistons, an upper piston rod extending outwardly and upwardly from the actuating chamber and connecting the upper piston with said iirst closure member, and a lower piston rod extending outwardly and downwardly from the actuating chamber and connecting the lower piston with said second closure member; conduit means communicating one end of the actuating chamber with the other end thereof; and means for applying pressure iluid to or bleeding pressure fluid from, selectively, said conduit means, the interior of the actuating chamber between said pistons, or said charging chamber.

6. 1n charging apparatus: a vertically disposed hollow yhousing constituting a charging chamber provided with downwardly facing upper inlet and lower outlet valve seats; a hollow body within the housing having a vertically oriented cylindrical actuating chamber formed therein and a pair of vertically spaced pistons slidable in the actuating chamber; axially aligned bores formed in the top and bottom of said body; upper and lower piston rods connected to said pistons and projecting through the top and bottom bores respectively; valve closure members fixed to the outer ends of said rods and arranged to sealingly contact said seats when in uppermost positions; and means for selectively controllably, supplying pressure iluid to and bleeding pressure uid from the central portion of the actuating chamber, between said pistons, and the ends of the actuating chamber.

7. The invention as stated in claim 6 wherein said closure members include resilient portions having upwardly convex surfaces sealing with said seats.

8. In charging apparatus: a hollow housing having a charging chamber therein and oppositely disposed inlet and outlet valve seats; a hollow body within the housing having a cylindrical actuating chamber formed therein and bores extending throughopposed ends of the body; a pair of pistons slidably mounted in the actuating chamber; piston rods connected to said pistons and extending outwardly of the body through said bores; valve closure members fixed to outer ends of said rods, each adapted to seal with one of said valve seats when the member is at one limit of travel; and means for selectively, controllably, supplying pressure fluid to and bleeding pressure uid from the ends of said actuating chamber and the central portion of the actuating chamber between said pistons.

9. In charging apparatus: a hollow housing having a charging chamber therein and upper inlet and lower outlet valve seats; a hollow body within the housing having a cylindrical actuating chamber formed therein and an open top and open bottom; upper and lower caps removably connected to top and bottom of the body, each having an axial bore therethrough; upper and lower pistons slidably mounted in the actuating chamber; a piston rod removably connected to each of said pistons and extending outwardly of the body through one of said bores; upper and lower valve closure members removably connected to the outer ends of said rods and adapted to seal with one of said valve seats when the member is at the upper limit of its travel; and means for selectively supplying pressure uid to and bleeding pressure uid from opposite ends of the actuating chamber and the central portion of the actuating chamber between the pistons.

10. The invention as stated in claim 9 including means for selectively supplying pressure iluid to and bleeding pressure uid from said charging chamber.

l1. The invention as stated in claim 10 wherein the effective area of said upper closure member exposed to uid in the charging chamber is at least about five times the eiective area of the upper surface of the upper piston.

No references cited. 

